1. Field of the Invention
The present invention relates to a novel extracted substance useful for antiviral inhibition against the human immunodeficiency virus (HIV) and a process for extracting the same. Specifically, the present invention relates to an extracted substance from a mixture of a non-fat starch from Ricini Semen and a root of Coptis sp. which exhibits a suitable anti-HIV activity without any side effects.
2. Description of the Prior Art
In 1983, it was found that HIV-1 is the causative agent of the acquired immunodeficiency syndrome (AIDS). Thereafter, several approaches to discover the genome of the virus and antiviral inhibitors thereof have been followed.
The selective infection of HIV on the helper T cell (T.sub.H) induces a disorder of immune system and subsequently results in AIDS. Reverse transcribed viral genome of the virus usually remains in a chromosome of host cells in the latent period. At the end of the period, the vital proliferation induces a cell fusion to produce syncytia, and subsequently kill cells by an acute infection. Otherwise, the viral proliferation is continued without any significant cytopathic effects by a chronic infection.
When the membrane protein gp 120 of the virus recognizes CD4 receptors present in host cells, the virus then attaches thereto. The virus enters cells and subsequently changes its gene from RNA to DNA using a reverse transcriptase, and finally enters the chromosome of host cells.
The vital genome is replicated in the cells by several signals and factors required in a host cell proliferation, and then a long protein chain is produced by an action of a transacting regulatory proteins expressed by the virus gene. As a specific protease for HIV is then acted on the proteins essential for vital replication, some of these proteins is transformed into glyco proteins and subsequently assembled each other to form the whole virus.
Accordingly, in order to develop anti-HIV drugs, the following inhibitory functions against the viral replication cycle should be established through a chemical therapy.
(a) inhibition of an action between gp120 of the virus and CD4 receptors of host cells, PA1 (b) inhibition of an action of a reverse transcriptase to change RNA of the virus into proviral DNA, PA1 (c) inhibition of an action of viral regulatory proteins, PA1 (d) inhibition of cleavage of vital precursor proteins, PA1 (e) inhibition of an action of a glucosidase or a mannosidase for a prevention of modifications into glycoproteins, and so forth.
A number of drugs having selective anti-viral efficacy have hitherto developed using differences between HIV and human host cells. Such drugs, especially inhibiting the viral cell proliferation include dextran sulfates and peptide T having an inhibitory function of (a) described above; dideoxycytidines, dideoxyinosines and phosphonoformates having a function of (b). Beside these, the examples are ribavirin, castanospermine, GLQ 223, antisense oligonucleotides, protease inhibitor, and so forth. However, these drugs are still not being commercially available for AIDS.
In addition, zidovudine (azidothymidine, AZT) is concurrently used as a medicine for AIDS, but has serious disadvantages in that this usually induces side effects including symptoms such as headaches, emesis, high fevers and spots, injuries of hematogenous systems, nervous systems, and suppression of the liver function, and that a resistance to the drugs is often found in a long-term therapy.
We, inventors of the present invention, have intensively conducted a wide range of experiments in order to develop a potent inhibitors having high treatment effects. As a result, we have discovered that a novel extracted substance isolated from Ricini Semen and a root of Coptis sp. has significantly improved activity, and could accomplish the present invention.